Q How does DACI operate?
A We have a small core staff and a network of seasoned senior consultants. This allows us to target the resources required for our various projects in a very cost-efficient manner.

Q If DACI does a design, analysis, or trouleshooting task for my company, will the task be done here, and will it require a lot of my staff's time?
A We usually perform tasks at DACI, and try to be as unobtrusive as possible. In some cases, we provide a design or analysis based only on submitted schematics and related design materials. However, that is not optimum. Instead we recommend that the process be a real-time effort with close coordination with your project managers. This will give them timely information during the design flow, enabling them to make important design decisions when changes are less costly.

Q What if my design team does not agree with your conclusions?
A Although we are highly qualified, we are not perfect. We expect our reports to be reviewed with a critical eye. In fact, "closing the loop" by comparing design/analysis results to lab or simulation results is a necessary step in ensuring that the results are correct and the design is fully understood. Ideally, the process is a dialog between the designers, analysts, and project managers with the goal of bullet-proofing and optimizing a design, in a cost-effective manner.

Q We have been using testing and simulations as our design validation process. Isn't that enough?
A Your competitors will hope you continue to think so. But your design validation process has a gaping hole.

Q Why is that? I thought analysis and simulation were the same thing.
A No, they are quite different. Simulation is an important tool, but does not facilitate an in-depth understanding of a design. Analysis on the other hand is the development and study of design equations. This allows the key variables of the design to be identified and their effects to be fully understood, essential for design-centering, optimization, and creativity. Analysis also takes into account tolerance stackup that is extremely difficult if not impossible to determine by testing or simulations, or by statistical methods such as Monte Carlo. Also, an important output of our WCA+ method is a probability estimate for out-of-spec conditions. This allows design managers to make rapid and practical risk assessments of any identified problems.

Q How can you use design equations to identify the complex performance aspects we observe with simulators?
A We have no objection to simulations being used as part of the preliminary design process to check out general concepts. However, when it comes time to dig into all of the details, simulations are not adequate for ensuring a highly reliable design. Equations, on the opther hand, are an open-ended modeling tool, providing tremendous insight. If a process can be observed, it can generally be broken into small manageable chunks and modeled with enough accuracy to meet design validation needs. Simulators such as SPICE are, after all, nothing more than equation generators running in the background. By comparison, with algebraic design equations you gain the advantage of much more clearly "seeing" a design, allowing the immense power of the human brain to be applied. As a small example, design equations can readily be adjusted to include the effects of thermal feedback within a power device such as an IGBT, allowing the design team to observe the conditions that initiate thermal runaway.

Q Can you analyze every design?
A No, but the exceptions are those relatively rare cases where a design relies on poorly understood or uncontrolled factors, or has an intertwined complexity which makes it impossible to unravel. In both cases, however, this is not a deficiency in the analysis process, this is a deficiency in the design. For a design to be of acceptable risk, it must be capable of being described with algebra or simple calculus, and able to survive a thorough analysis.

Q Some of my designers do not provide much analytical backup for their designs. Others do not like to have their designs "challenged." Will you still be able to do an analysis?
A Yes. Our background includes in-depth design experience, and we are sensitive to such issues. Our role is not to be critical, but to be viewed as an assistant to the design team and project manager, helping them to beef-up, tune-up, and optimize a design.

FAQ

Everything you need for cost-effective and highly reliable circuit design

Circuit failures costing you time & money? We can help. Please email me at daci@daci-wca.com, or leave a message at (813) 975-7278.

Ed Walker is President of Design/Analysis Consultants, Inc. Prior to founding DACI in 1983, Walker worked for both defense and commercial firms as an electronics design engineer. DACI has become a leading firm in the field of design validation for product reliability. DACI's customers have included industrial, commercial, military, and medical firms.

Walker is the author of The Design Analysis Handbook, A Practical Guide to Design Validation, and the Design Master™ software, a worst case analysis tool adopted by numerous technology firms.

In addition to providing design and development services, Walker has used his troubleshooting skills to help clients resolve numerous problems. Walker has also provided expert testimony to help resolve litigation concerning technical performance and limitations, and has been granted several patents.